Flushing system for waterway-basins.



No. 782,965. PATENTED FEB. 21, 1905.

w. s. ISHAM. FLUSHING SYSTEM FOR WATERWAY BASINS.

[NI/ENTOR APPLIOATIOH FILED HOV.3G,1904.

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Patented February 21, 1905.

PATENT OEEIcE.

WILLARD S. ISHAM, OF WASHINGTON, DISTRICT OF COLUMBIA.

FLUSHING SYSTEM FOR WATERWAY-BASINS.

SPECIFICATION forming part of Letters Patent No. 782,965, dated February 21, 1905.

Application filed November 30, 1904. Serial No. 234,866.

To all whom it may concern:

Be it known that I, WILLARD S. IsIIAM, a citizen of the United States, residing at IVashington, in the District of Columbia, have invented new and useful Improvements in Flushing Systems for Waterway-Basins, of which the following is aspecification.

My invention relates to a system for preventing the silting up of reservoirs or basins formed in waterways.

The general object of my invention is to provide means whereby the silt deposited by the water or detritus rolled along by the water will be removed from the reservoir or basin in an economical manner, thereby reducing or entirely avoiding the expense of dredging said silt or detritus.

WVith this general object in view my invention consists in the features, details of construction. and combination of parts, which will first be described in connection with the accompanying drawings and then particularly pointed out in the claims.

-In the drawings, Figure 1 is a diagrammatic sectional view illustrating a reservoir or basin in awaterway provided with the preferred form of my invention; Fig. 2, an enlarged transverse sectional view taken on theline 2 2, Fig. -1; Fig. 3, a similar View on the line 3 3, Fig. 1.

Referring to the drawings, A, Fig. 1, is a dam located in a waterway, such as a canal or stream employed for transportation, power, or irrigation purposes. The dam holds back the water, and thereby forms a reservoir or basin, in which the surface of the Water is indicated by the dotted line B, Fig. 1. Such a basin is usually formed in canals or streams in order to form a reservoir for storing water for power, irrigation, or canal purposes. Under such conditions it has been found in actual practice that owing to the decrease in movement of the water insuch basins a large amount of silt and detritusis deposited in the basin, the larger amount of course being brought into said basin during the flood season of the year. The result has been that many reservoirs or basins of this kind have been almost entirely filled or silted up in the course of a few years where dredging has not been resorted to. To prevent such silting up, it has been common to dredge such basins at the required intervals, and particularly after the flood season has passed and the silt and detritus have been deposited by the flood-water as it passed through the basin on its way out of the same.

The silting up of a basin proceeds progressively, commencing first at the upper or inlet end of the basin, where the incoming water is first checked in its course. When the silting at this point has progressed to a point which shallows the waterway sufficiently, the silt is carried farther along and then deposited, thus gradually but often rapidly filling the entire bottom of the reservoir to an extent sufficient to render the same useless for the purpose for which it was intended.

I am aware that gates located at the bottom of dams forming small reservoirs have been employed to remove deposited silt in their vicinity. Such gates, however, are not successful for large basins where capacity is required, for the reason that only that part of the silt near the dam can be removed, and meantime the inlet end of the basin is being rendered useless, defeating the purpose for which the entire basin was created. Furthermore, the use of such-gates has the disadvantage that they cause a rapid movement of the water and a scouring of the bottom of the basin near the foot of the dam below the openings, thus increasing the danger of undermining the dam at such points, and consequently necessitating a special construction of the foundations of the dam in order to minimize such danger.

In my invention 1 provide a discharge outlet or outlets at the point of maximum deposit viz., at or in proximity to the point of inlet of the water to the basin, or, in other words, at the upper end of the basin-such a dischargeoutlet being indicated at C and consisting in the example shown of a pier havinga vertical opening 0, connected with a conduit D, lead ing outside the reservoir, said pier also having a connection with the basin at or near the bottom of said basinas, for example, through the lateral openings 0, Fig. 2. The outer ends of these openings 0 are preferably provided with suitable gratings to prevent driftwood, logs, or large stones from choking the discharge-outlet. The bars of such gratings are indicated at a, Fig. 2. I also provide suitable means for controlling the discharge-outlet, which means in the present instance consists of gates 0 arranged to close the inner ends of the lateral openings 0', said gates having their operating-rods 0 extended above the water-level and arranged to be operated by suitable means, whereby the gates 0 may be opened and closed. In the structure illustrated this operating means comprises a screwthread on each operating-rod, a nut 0 for each rod, said nuts having their peripheries arranged as worms, which are engaged by wormscrews 0 provided with hand-wheels 0 The rotation of the said hand-wheels in the desired direction will rotate the nuts 0 and thus lift or lower the gates c and open or close the gates, according to the direction of rotation of said hand-wheels.

The conduit D may extend in any desired direction to a point where it can discharge outside the basin.

In addition to supplying a discharge-outlet at the point of initial deposit of the silt or cletritus in the preferred embodiment of my invention I also provide one or more additional discharge-outlets in proximity to the bottom of the reservoir, thus giving, with the discharge-outlet at the point of initial deposit, a plurality of discharge outlets distributed along the bottom of the basin. These discharge-outlets may be constructed the same as that already described and shown at C or may have some other formsuch, for example, as is shown at E, Fig. 3consisting in this case of a gate-valve opening upward through the bottom of the reservoir, the gate a being substantially horizontal and operated by a rod 0, which may have a universal joint 0 to allow the outer half of the rod to extend upward at an incline, the upper end, which extends above the water-level, being provided with suitable means for operating itsuch, for example, as a crank a. The rod may be supported by suitable bearings a, as indicated in Fig. 3.

In the construction shown in the drawings the plurality of discharge-outlets instead of being each independent of the others are united to a common conduitas, for example, the conduit 1), which in this case extends through the dam and discharges outside or beyond the same. This conduit D is preferably located below the bed of the basin.

The discharge-outlets are distributed, preferably, at such distances apart that they can always be used to prevent the accumulation between them of a depth of silt or detritus greater than permissible. It is of advantage to locate them at distances apart which do not exceed double the permissible depth of deposit of solid matter in the basin multiplied by the tangent of the angle of slope of such solid matter.

While in ordinary constructions the surplus flood-water must go over the dam, through openings in the dam, through waste-weirs or the like, leaving behind itself a large accumulation of silt to be subsequently removed at great expense, in my system this surplus flood-water is employed to remove not only the silt or detritus which it carries with itself into the basin, but also any other silt or detritus which may have been accumulated during the season of slack water, so that at the end of the flood season instead of the basin being left with an increased deposit of solid matter it is scoured out to the maximum extent and is thus in a better position to contain the limitedamount of silt which will accumulate before the next flood season without interfering with the purposes for which the basin was intendedthat is, without interfering with the navigable depth of water or appreciably diminishing the storage capacity of the basin.

The operation of my system consists merely in the opening of the gates at such times as there is any waste water to be disposed of, thereby allowing such waste water to scour out and carry off any silt or detritus which is in proximity to the discharge-outlets and also allowing it to carry along with itself any silt or detritus which it has brought into the basin.

The gates are to be closed during those seasons when the water must be retained in the reservoir; but at such times little silting occurs, for if there is little or no water flowing in from the stream above there can be little or no solid matter brought into the basin.

It will be noted that my invention has the important advantage that the surplus floodwater is used to carry off its own silt, and thus the said silt is prevented from accumulating in the reservoir at the flood season, whereby the expense of dredging the silt is avoided.

Having thus fully described my invention, what I claim is 1. In reservoirs or dams for the accumulation and storage of water, means to prevent the accumulation of silt in such reservoirs, comprising a discharge-conduit leading from near the bottom in proximity to the inlet of said reservoir.

2. In reservoirs or dams for the accumulation and storage of water, means to prevent the accumulation of silt in such reservoirs, comprising a plurality of discharge-outlets opening into said basin near the bottom thereof.

3. In reservoirs or dams for the accumulation and storage of water, means to prevent the accumulation of silt in such reservoirs, comprising a discharge-conduit leading from near the bottom in proximity to the initial point of deposit of the silt in said reservoir.

4. In reservoirs or dams for the accumulation and storage of water, means to prevent consisting of a conduit system having a pinrality of openings distributed along the bottom of the basin at distances apart not exceeding double the permissible depth of deposit of solid matter in said basin multiplied by the tangent of the angle of slope of such solid matter.

In testimony whereof I aflix my signature in presence of two subscribing Witnesses.

WILLARD S. ISHAM.

Witnesses:

M. C. MASSIE, ALBANUs S. T. JoI-INsoN. 

